Audio oscillator design still practical?

Thread Starter

upand_at_them

Joined May 15, 2010
940
I could find use for this on my test bench: http://www.redcircuits.com//Page82.htm

But I see that the design comes from the 1980's. Is it still worth building? How does it compare to the cheap DDS modules available now? And what about building an adjustable Wein bridge? Should I shutup, build it, and see for myself?
 

bertus

Joined Apr 5, 2008
22,270
Hello,

The NE5532 and TL084 are pretty good opamps.
The stability is made with the LED(D5)/LDR(R9) combination.
Put them together in a light tight box.

Bertus
 

OBW0549

Joined Mar 2, 2015
3,566
But I see that the design comes from the 1980's. Is it still worth building?
Who knows? Only one way to find out, and that's to build it and see. Nothing wrong with designs from the 1980's, unless they relied on obsolete components for proper operation.

How does it compare to the cheap DDS modules available now?
I'm not familiar with those, but DDS as a sine wave generation technique has (when done right) a couple of outstanding characteristics: extreme frequency accuracy and stability due to the low cost of accurate, stable crystal oscillators, and absolute repeatability. When these qualities are important, DDS stands head and shoulders above any other technique. DDS is not too good for getting very low THD at low frequencies, though, because of the limited resolution (often no more than 10 bits) of the synthesis DAC.

And what about building an adjustable Wein bridge?
A Wein bridge oscillator would work just fine.

Should I shutup, build it, and see for myself?
The "build it and see" part is good. I don't like the "shutup" part, though; I'd like to hear what kind of results you get from this circuit.

Meanwhile, here's a good application note on sine wave generation techniques:

http://www.ti.com/lit/an/snoa665c/snoa665c.pdf
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
Okay, good. Do you think I can get away with building it on protoboard and point-to-point wiring? (I've never done a PCB design.)
 

Brownout

Joined Jan 10, 2012
2,390
Download LTSpice and simulate it before building it. Make sure it works as advertised, and explore the functionality before going to all the trouble.
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
I'm about to place a parts order through Tayda. They have everything except the 220pF 63V Polystyrene capacitors. The only thing that's close is 220pF 50V Monolithic Ceramic. Does it really need to be polystyrene?
 
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